The present invention relates to selective switching of a pump of a spray apparatus from continuous operation to intermittent manual operation. The invention has particular use in conjunction with spray apparatus in the form of a pressure washer, like that disclosed in U.S. patent application Ser. No. 297,620 filed Jan. 17, 1989.
A pressure washer is a relatively small size liquid pumping apparatus which delivers liquid at high pressure through its outlet. The pressure of the sprayed liquid is relied upon for its cleaning and spraying functions. Pressure washers are typically operated by electric pumps, although fuel operated pumps may be used. There are various known controls for the flow through the pressure washer outlet, including controls for selectively turning on and off the pump of the pressure washer and/or a valve in the outlet from the pressure washer, typically at or toward its spray nozzle, which is manually operable by the operator to selectively permit or block the outlet flow.
Where the pressure washer pump continues to operate while the outlet spray nozzle valve is closed, the liquid that is being pumped, but that is not then being sprayed out, must be accommodated. Typically, that liquid still being pumped is recycled to an earlier location in the liquid flow pathway, upstream of the pump, to be recirculated to the pump. When the outlet spray nozzle is open, recirculation stops and the liquid is sprayed out. Recirculating means are known for pressure washers, and they are not detailed herein.
The pressure washer with which the present invention is employed includes a pump and apparatus, not disclosed in detail herein, for pumping and supplying a spray of water or a mixture of water with a cleaning liquid upon activation of an electric pump. There is an outlet from the pressure washer to which is connected a selected outlet conduit, which terminates in a spray nozzle. A switch on the pressure washer is operable by the user of the pressure washer to activate the pump. The switch is operated by a manually operable button. When that button is manually moved in one direction, the switch closes a circuit to activate the electric pump. When that button is moved in the opposite direction, the switch opens the circuit to deactivate the pump.